Traditionally, household appliance controls have been based on mechanical components. Mechanical timers, relays, and solenoids were used to effect various cycles of operation, opening and closing circuits, and actuating mechanical assemblies. Through decades of design and refinement, these controls provide a lost cost approach of achieving the basic functionality found in many household appliances.
However, mechanical assemblies and components are only reliable to a certain extent. For example, mechanical relays or timers are generally reliable for a certain number of hours of use, but beyond this level, their reliability decreases. Since failure of a single component often renders the whole appliance non-functional, improving the reliability of the appliance past a certain point is difficult while maintaining costs of the components within certain constraints.
Further, mechanical assemblies and components are designed typically to only perform basic functions. There is limited flexibility as to what the mechanical assemblies can do and how they can operate. Implementing new functions or user features is typically not possible with the existing mechanical assemblies. For example, piezoelectric buzzers are commonly employed in appliances, but the control circuitry is limited, and typically capable of only providing a singe frequency ‘beep’ as feedback to the user, typically in regard to notification of an error or an event (timer expiry).
Many household appliances are now becoming more “intelligent” by incorporating microcontrollers, which is feasible in part due to the low price of such microcontrollers. Many aspects of the operation are now controlled not by mechanical relays and devices, but by a microprocessor executing control software. Further, software allows greater flexibility in providing new features and modes of operation.
In particular, the use of microprocessors dedicated to controlling a household appliance allows greater flexibility in interacting with the user of the device. Thus, various displays, modes of operation, and user feedback can be provided to a user by using the same microprocessor used to control the appliance.
One approach for using a microprocessor is disclosed in U.S. Pat. No. 4,490,488 to Pearman et al. Although the cost of microprocessors have become less expensive, Pearman discloses using a touch screen display and/or a tactile keyboard input which not only significantly increases the cost of the appliance, but may not be desirable from a human design and marketing aspect.
Thus, a need exists for a flexible, yet inexpensive, systems and methods of providing enhanced user interaction with a household appliance.